Selector valve



Oct. 14, 1969 l P. H. DUGAY 3,

SELECTOR VALVE Filed Aug. 5, 1964 2 Sheets-Sheet 1 FIG.

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United States Patent Int. Cl. F16k 11/14,- F1511 1/00 U.S. 'Cl. 137-112 6 Claims ABSTRACT OF THE DISCLOSURE A hydraulic circuit including a receiver, a high pressure line -to the receiver, a low pressure line from the receiver, a plurality of hydraulic pumps, a plurality of corresponding supply tanks, high pressure lines from each ofrthe pumps and low pressure return lines to each of the tanks and a selector valve attached to have the receiver either supplied by one of the pumps or placed in a stand-by position, the selector valve comprising one body, separate casing in said body, one of said casings being connected with said low-pressure line from said receiver and with said return low-pressure lines to said tanks and the others of said casings being each connected respectively with said high pressure line to said receiver and with one of said high-pressure lines from said pumps, and one sliding valve in each of said casings, each said sliding valve having only two bearing surfaces.

This invention relates to hydraulic circuits and more particularly to a selector va1vei.e., a valve therefor which, in association with a number of independent hydraulic generating systems, enables any one of such systems to supply a receiver or which can be placed in an off or stand-by position.

Objects of the present invention are to provide a selector valve having the characteristics that it is substantially unafiected by temperature variations and gradients and gives very small leakages; that can provide satisfactory equalisation which is independent of the high and low pressures in each generating system and has high reliability and long life; that the high pressures of each circuit are operative in separate casings, so that the breakage of any one casing does not cause oil to be lost from the other casings, and that the number of moving gaskets is reduced very considerably and, that moving gaskets are provided only on one of the high-pressure circuits.

According to the invention a selection valve in a hydraulic circuit comprises in a single body, piston valves associated respectively with each of the generating systems and with the return to the supply tanks, the piston valves being mounted in separate casings and each comprising only two bearing surfaces. Advantageously, the piston valves are under the control of a single handle or the like operating a rotatable spindle which has the only moving gaskets of the entire system.

In one embodiment, the selector valve has, on one side of the rotatable control spindle, two parallel piston valves to which the high-pressure lines from each of the two generators to the receiver are respectively connected and, on the other side of said spindle, a piston valve whose cross-section is twice the cross-section of either of the first-mentioned two piston valves and to which the common low-pressure return lines from the receiver and from the valve to the two supply reservoirs are connected.

The two high-pressure valves can each comprise a pressure-equalising chamber connected to a line extending to the chamber of the low-pressure piston valve which latter chamber in turn communicates with one of the returns to the generator supply tanks. Advantageously, the

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pistons of the high-pressure piston valves are each formed with at least one groove in the periphery of one of their bearing surfaces, such groove communicating via radial and axial ducting with the respective tank returns ofthe two generators, and the three piston valves extend into a common chamber connected to one of the generator tank returns.

The accompanying drawings show purely by way of example an embodiment of a selector valve according to the invention.

In the drawings:

FIG. 1 is a diagram of the circuits controlled by the selector valve;

FIG. 2 is a view of the selector valve in longitudinal section through the plane passing through the pistonvalve axes;

FIG. 3 is a section taken along the line III--III of FIG. 2;

FIG. 4 is a section taken along the line IVIV of FIG. 3;

FIG. 5 is an end view of the valve looking in the direction of the arrow V in FIG. 2, and

FIGS. 6 and 7 are sections taken along the respective section lines VIVI and VII-VII of FIG. 2.

In the embodiment shown in the drawings, a selector valve is provided via which a receiver 1, shown in FIG. 1, can either be supplied by, or completely cut olf from (standby position), either of two hydraulic generators 2, 3. The selector valve is connected to the generators via 5 lineshigh-pressure lines 4, 5 from the generators 2, 3 respectively, a low-pressure return line 6 to the supply tank of the generator 2, and two low-pressure return lines 7, 8 to the supply tank of the generator 3. The selector valve is connected to the receiver 1 via only 3 linestwo high-pressure supply lines 9, 10 respectively associated with each generator 2, 3, and a single lowpressure line 11 leading back to the two generators. A pressure discriminator valve 12 at which the lines 9, 10 terminate connects the receiver 1, via a line 13, to whichever line 9 or 10 is at the higher pressure, the line at the lower pressure being closed by the valve 12.

The actual selector valve, details of which are shown in FIGS. 2-7, comprises a body 14 and, disposed therein, three piston valves 15, 16 and 17 moving in respective casings 18, 19 and 20 which are completely independent of one another and which can be dismantled separately. Each casing has a respective sleeve or jacket 21, 22 and 23. The piston valves 15, 16 have the same cross-section as one another, and the piston valve 117 has twice the cross-section of either of the piston valves 15, 16. These piston valves or pistons are each provided at their inner end with respective grooves 24, 25 and 26 engaged by rollers 27, 28 fitted to the end of arms 29, 30 rigidly connected to a spindle 31 adapted to be rotated by an outside handle or the like. The spindle 31 has two annular sealing glands 32, 32'.

The jacket 21 of the casing 18 is pierced with two groups of apertures 33, 34 disposed at an axial distance from one another which is slightly less than the axial distance between the heads or bearing surfaces 35, 36 of the piston 15; the casing 18 has two connections 37, 38 to which the lines '9, 4 respectively are connected and which communicate permanently with the apertures 33, 34 respectively. The jacket '22 of the casing 19 is pierced with two groups of apertures 39, 40 which are disposed at an axial distance from one another slightly less than the axial distance between bearing surfaces 41, 42 of the piston 16; the casing 19 has two connections 43, 44 to which the lines 10, 5 respectively are connected and which communicate permanently with the apertures 39, 40 respectively as is seen in FIG. 3. The jacket 23 of the casing 20 is pierced with three groups of apertures 45, 46 and 47 which are separated from one another by axial spacings less than the axial spacing between bearing surfaces 48, 49 of the piston 17; the casing 20 has three connections 50, 51 and 52 to which the lines 6, 11, 8 are connected and which communicate permanently with the apertures 45, 46 and 47 respectively.

When the arm 30 is rotated anticlockwise, as shown in FIG. 3, to form an angle of 30 with the vertical shown by position I of FIG. 1, the bearing surface 36 of the piston 15 closes the apertures 34. The apertures 33, and therefore the connection 37 and the supply line 9, are in the closed state. The bearing surface 42 of t e piston 16 leaves the apertures 40, and therefore the connection 44 and apertures 39 and connection 43, open. The line is in the closed state and the line communicates with a cavity 53 common to the three piston valves -17. With the valve 17 in this position, the cavity 53 communicates via the apertures 45 with the connection and therefore with the line 6; the connections 50, 51, and therefore the lines 6 and 11, are interconnected, and the line 8 extends via the connection 52 and apertures 47 into a closed cavity.

The position just described is the off or stand-by position in which the supply line 9 from the generator 2 is closed, the line 10 from the generator 3 is connected to the line 6i.e., to the reservoir of the generator 2 and the common return line 11 is also connected to the line 6.

When the arm 30 is turned into the intermediate position forming an angle of 8 with the vertical and shown in FIGS. 2 and 3, and by position II of FIG. 1, it will be apparent that the lines 3 and 4 are interconnected via the apertures or ports 33, 34 of the casing 18, the position of the valve 16 is such that the line 10 is still connected to the line 6 via the apertures 40, the cavity 53 and the apertures 45 in the casing 20, and the position of the valve 17 is such that the line 11 is still connected via the apertures 45 and 46 to the line 6.

In this position, the generator 2 supplies the receiver 1.

If the arm 30 is turned further clockwise to its righthand position in FIG. 3, it passes through a position, in which the valve 16 cuts off the line 10 from the line 6, then connects it to the line 8 via a radial duct 54 and axial duct 55 of the piston 16 and an equalising chamber 56 of the valve 16 which, like equalising chamber 57 of the valve 15, communicates via axial ducts 58, 59 and radial ducts 69, 61 with a longitudinal duct 62, the same extending into the valve casing 20 in communication with the apertures 47.

The handle then passes through a position in which the apertures 33 are closedi.e., the line 9 is cut off from the line 4, then connected to the line 6 via a radial duct 63 and axial duct 64 0f the piston 15 and via the common chamber 53. The piston 17 then closes the apertures 45, isolates the line 11 from the line 6, then interconnects the apertures 46 and 47 and therefore connects the line 11 to the line 8. When the valve 16 has moved far enough to the right (FIGS. 2 and 3) for the duct 54 to be out of register with the apertures 40, the line 10 is disconnected from the line 8, then connected to the line 5, the apertures 39 and 40 communicating with one another.

When the arm 30 makes an angle of +30" with the vertical, as in the right-hand position in FIG. 3, the line 9 is disconnected from the line 6 and connected to the line 7 which can be the same as the line 8. Lines 7 and 8 both connect port 52 of casing 20 to the same supply tank of the hydraulic generator 3, therefore, as seen in FIG- URE 1 one line may be used instead of the two shown. Referring to FIGURE 3 the connection between casing 26 and casing 18 clearly indicates that the flow could be directly from casing 18 through casing 26 into the aforementioned single line rather than having a line leading from casing 18 and a line leading from casing 29. This connection is by way of the apertures 33 which communicate with the equalising chamber 57. Equalizing chamber 57 of the valve 15 communicates via axial ducts 58, 59 and radial ducts 60, 61 with a longitudinal duct 62, the same extending into the valve casing 26 in alignment with the apertures 47. In this position of the selector valve, shown by position III of FIG. 1, the generator 3 supplies the receiver 1.

The selector valve hereinbefore described is a useful compromise between the demands of reliability and weight, for it is connected to the receiver by only 3 linesthe two high-pressure lines 9, 10 each associated with a generating systemso that both circuits are-not lost in the event of a high-pressure line breakingand a single low-pressure line 11 common to the two generating systems, since there is much less likelihood of a low-pressure line breaking. The oil of the two circuits cannot mix if the pressure discriminator valve 12 leaks (the unused high-pressure line 9, 10 is connected via the selector valve to the supply tank of tr e circuit in use) nor in the case of leakage in the selector valve, since the expansion grooves collect such leaked fluid and return it to the appropriate tank.

The sequences used for the various synchronisation operations of the valves 1517 by the single control spindle 31 is such that the valve cannot produce brief or accidental pressure surges in the return circuit nor cause large leaks between the high-pressure and low-pressure sides.

What I claim is:

1. In an hydraulic circuit comprising a receiver, a high pressure line from a pressure-discriminating valve to said receiver, a low-pressure line from said receiver, a plurality of hydraulic pumps, a plurality of corresponding supply tanks, high-pressure lines from each of said pumps, return low-pressure lines to each of said tanks, a selector valve adapted to have said receiver either supplied by one of said pumps or placed in a stand-by position, said selector valve comprising one body, separate casings in said body, one of said casings being connected with said low-pressure line from said receiver and with said return low-pressure lines to said tanks and the others of said casings being each connected respectively with said high pressure line to said receiver and with one of said high-pressure lines from said pumps, and one sliding valve in each of said casings, each said sliding valve having only two bearing surfaces.

2. In an hydraulic circuit as in claim 1, one single rotatable spindle connected with said sliding valves and having sealing glands where it passes through said body and an actuating member for said spindle to control said valves.

3. In an hydraulic circuit comprising a receiver, a high pressure line through a pressure-discriminating valve to said receiver, a low-pressure line from said receiver, a plurality of hydraulic pumps, a plurality of corresponding supply tanks, high-pressure lines from each of said pumps, return low-pressure lines to each of said tanks and a selector valve adapted to have said receiver either supplied by one of said pumps or placed in a stand-by position, said selector valve comprising one body, a transversely disposed rotatable spindle having sealing glands, an actuating member for said spindle, longitudinal parallel cylindrical casings arranged on one side of said spindle and each connected respectively with said high pressure line to said receiver and with one of said high-pressure lines from said pumps, a longitudinal cylindrical casing arranged on the other side of said spindle parallel to said casings arranged on said one side, having a section area equal to the total of the sections area of said latter casings and connected with said low-pressure line from said receiver and with said return low-pressure lines to said tanks and one sliding valve in each of said casings, each said sliding valve having only two bearing surfaces.

4. In an hydraulic circuit comprising a receiver, a high pressure line through a pressure-discriminating valve to said receiver, a low-pressure line from said receiver, a plurality of hydraulic pumps, a plurality of corresponding supply tanks, high-pressure lines from each of said pumps, return low-pressure lines to each of said tanks and a selector valve adapted to have said receiver either supplied by one of said pumps or placed in a stand-by position, said selector valve comprising one body, separate casings in said body, one of said casings being connected with said low-pressure line from said receiver and with said return low-pressure lines to said tanks and the others of said casings being each connected respectively with said high-pressure line to said receiver and with one of said high-pressure lines from said pumps, a sliding valve having only two bearing surfaces in each of said casings connected with the high-pressure lines, defining in said corresponding casings a pressure equalizing chamber, a sliding valve having only two bearing surfaces in said casing connected with the low-pressure lines and defining return low-pressure chambers, and a conduit connecting said pressure equalizing chambers with one of said return low-pressure chambers.

5. In an hydraulic circuit comprising a receiver, a high pressure line through a pressure-discriminating valve to said receiver, a low-pressure line from said receiver, a plurality of hydraulic pumps, a plurality of corresponding supply tanks, high-pessure lines from each of said pumps, return low-pressure lines to each of said tanks and a selector valve adapted to have said receiver either supplied by one of said pumps or placed in a stand-by position, said selector valve comprising one body, separate casings in said body, one of said casings being connected with said low-pressure line from said receiver and with said return low-pressure lines to said tanks and the others of said casings being each connected respectively with said high-pressure line to said receiver and with one of said high-pressure lines from said pumps, a sliding valve having only two bearing surfaces in each of said casings connected with said high-pressure lines, one of said bearing surfaces being formed with at least one peripheral groove, a sliding valve having only two bearing surfaces in said casing connected with the low-pressure lines and defining return low-pressure chambers, and radial and axial ducts connecting said grooves with said corresponding return low-pressure chambers respectively.

6. In an hydraulic circuit comprising a receiver, a high pressure line through a pressure-discriminating valve to said receiver, a low-pressure line from said receiver, a plurality of hydraulic pumps, a plurality of corresponding supply tanks, high-pressure lines from each of said pumps, return low-pressure lines to each of said tanks and a selector valve adapted to have said receiver either supplied by one of said pumps or placed in a stand-by position, said selector valve comprising one body, separate casings in said body, one of said casings being connected with said low-pressure line from said receiver and with said return low-pressure lines to said tanks and the others of said casings being each connected respectively with said high-pressure line to said receiver and with one of said high-pressure lines from said pumps, a sliding valve having only two bearing surfaces in each of said casings connected with said high-pressure lines, a sliding valve having only two bearing surfaces in said casing connected with the low-pressure lines and defining return low-pressure chambers, all of said casings extending into one common chamber, and conduit means connecting said common chamber with one of said return low-pressure chambers.

References Cited UNITED STATES PATENTS 1,789,841 1/1931 Rennick 137-563 2,808,130 10/1957 Merritt 25l-3 19 2,944,597 7/1960 Wilson 137567 M. CARY NELSON, Primary Examiner WILLIAM R. CLINE, Assistant Examiner US. Cl. X.R. 137-567 

